1. Field of the Invention
The present invention relates generally to a cooling system for cooling an engine of an automotive vehicle. More particularly, the present invention relates to an ejector system used in an automotive cooling system which substantially reduces recirculation of air into the fan of the cooling system.
2. Disclosure Information
Most vehicles used today are propelled by internal combustion engines and such engines, as is well known, generate heat during their operation. For the most part, the internal combustion engines employed commercially are of the liquid-cooled type which employs the circulation of a coolant through the engine for absorbing heat. The correct operating temperature of the engine is maintained by subsequently passing, under pressure, the heated coolant received from the engine through a heat exchanger system and returning the coolant to the engine for recirculation therein. Generally, the heat exchange system employed includes a heat exchanger or a radiator and condenser assembly through which the heated coolant received from the engine flows. Simultaneously, the fan disposed between the radiator and the engine draws ambient air through the radiator which absorbs the heat from the heated coolant and carries it to the atmosphere. In most vehicle applications, the air stream formed by the fan is discharged back over the engine after passing through the radiator. This engine fan exhaust impinges on the engine block of the vehicle engine and is turned approximately 90.degree. downward. This hot exhaust air then impacts the ground and a portion of the fan exhaust is redirected toward the front of the vehicle where the hot air flow is subsequently reingested into the front-end air stream. This recirculation results in increased engine coolant air inlet temperatures and subsequently increased air conditioning head pressure. This is particularly a problem when the vehicle is at idle in hot regions.
Various devices have been proposed to reduce or eliminate the hot air recirculating back to the front end intake of the vehicle. For example, U.S. Pat. No. 4,173,995 discloses a recirculation barrier for a heat transfer system for an automotive vehicle. The patent teaches eliminating air flow recirculation in the fan shroud-hub region of the vehicle by contouring the fan shroud and installing a deflection plate which turns the flow of air from an axial to a radial direction, thereby reducing the amount of air flow recirculating in the fan shroud region. By reducing the amount of recirculation in the fan shroud, the fan operates more efficiently and more cooling air is pulled through the fan/radiator. This system does not disclose the use of an ejector for reducing the amount of recirculation of the hot air into the fan intake.
Ejectors have been utilized in the aerospace industry to increase engine thrust by increasing primary and bypass air stream mixing. Heretofore, however, an ejector has never been utilized in the automotive environment for reducing air flow recirculation, particularly when an automotive vehicle is at idle conditions. It is, therefore, an object of the present invention to reduce the air conditioning head pressure during idle condition by decreasing engine air flow recirculation without effecting engine cooling performance.